Local transdermal delivery of drugs, while desirable, is limited by current technologies. Few pharmaceutical entities have successfully been delivered transdermally in effective dosages. For example, a limited number of drugs, such as steroids, nicotine and nitroglycerine, which are non-charged and do not form hydrogen bonds, have been successfully delivered by passive diffusion, relying on the concentration gradient between outside and inside the skin to deliver the agent in accordance with Fick's first law of diffusion. The amount of pharmaceutical agent that can be delivered through simple diffusion is also limited. For instance, once the concentration inside the stratum corneum becomes equal to that outside, flow of pharmaceutical agent may stop. Thus, improvements in the transdermal delivery of substances, locally or systemically, are needed.